Abstract: In order to realize the automatic steering of agricultural equipment, a highly integrated system of automatic steering device for agricultural machinery is designed by using a DC motor to drive hydraulic redirector after amplifying the torque through a gear reducer.This system includes the automatic steering control structure, the controller circuit and its wheel steering precise servo control algorithm.The controller adopts Freescale automotive grade chip and considers the unsafe steering situation when the agricultural machine is not started, which makes the control logic safe and more reliable. The electro-hydraulic steering model of the front wheels is established by Matlab, and the simulation experiments with different steering angle signals are carried out to verify the response characteristics of the control algorithm in this paper. The device is installed on the highland gap planting robot and the experimental results show that the wheel turning angle control error is less than 0. 2°, the overshoot is less than 2%, and the fastest response time of ±20° steering is 1. 3s. The automatic steering control system has good control effect and can meet the automatic steering of common agricultural machines.